The bullet ant is aptly named -- with the most painful insect sting said to rival the agony of a bullet wound. Few, save perhaps the odd tropical poacher, have endured the pain of both. One of my fellow biologists had his first encounter with Paraponera clavata, while harnessed a hundred feet in a tree. “I thought I had been bitten by a venomous snake” he recalls, “but looking down saw instead three bullet ants stinging my leg.” A relief to be sure, but only in the mind. The throbbing would last for 24 hours, giving this ant another name- hormigas veinticuatro.
Painfully aware of this, I set out from La Selva station in Costa Rica, hunting for bullet ants. The second largest ant in the world, she shouldn’t be hard to find, right? I trekked the many jungle trails, ever mindful of the venomous snakes and golden Nephila spider webs which draped themselves off nearby trees. Partway down an overgrown trail, I spotted her – an inch long, sleekly black, with a long thin waist and huge mandibles. The worker bullet ant was foraging on a fallen log across the trail. I waited patiently for her to bring her grasshopper prey home. Where do you live little one? She clambered over to a sapling, barely two inches wide, and disappeared into the ground. My eyes lit up- it was a perfect nest for my mad science. My mission was crazy, totally insane. My goal was to enrage, and capture alive, hundreds of living bullets. And to do so, I would dig up this nest.
There are so many things we don’t know about these and other ants, particularly how they communicate with one another. I wanted to know whether different ants in the nest- foragers, guards, nurses, queen- told each other about their roles through different chemical labels. To get the nurses and queens, I needed to delve deep into the nest’s darkest chambers. And the ants needed to be collected alive for their chemical nametags to remain intact.
Such chemical nametags are commonly used by ants to communicate identity. Not quite ‘hi my name is Barbara the bullet ant’, but information such as occupation, reproductive status, and colony membership. The chemicals in question are called cuticular hydrocarbons, waxy substances on the exoskeletons of most insects. Initially used as a protective barrier against desiccation and microbes, ants have evolved to express a language of hundreds of hydrocarbons. My research aims to decipher this language, and maybe one day by manipulating their chemical vocabulary, talk to the ants.
The next day dawned as any other, but I had to take a deep breath as I prepared myself. I gathered my tools- a couple of buckets coated in fluon (a slippery substance ants generally cannot crawl up), shovels, and long metal forceps for grabbing squirrelly ants.
I tucked my two epipens into my backpack. Just like the honeybee, the sting venom of an ant can also cause an allergic reaction. And there is no telling how the body will react to a potent neurotoxic venom it has never encountered before. Uninitiated into the tropical biologists ‘stung-by-bala’ crowd, I was convinced today was the day to be baptized into the club. The mystery of the sting had bewitched me. But unlike most members, I would be facing not a single stray forager, surprised and scared, but hundreds of furious ants determined to protect their home.
Even so, I had miraculously recruited an eager, but also bullet-ant-naïve, undergrad helper named Walter. Together we trudged out to the nest site, buckets and shovels in tow. Our anxiety was palpable as we sweated through the jungle. We cut the tension with nervous conversation. Finally we reached the spot. A spindly tree, the smallest I had ever found a nest under, reached out over the trail. The plan was to collect as many workers as possible with our forceps, tossing them into our buckets and hopefully dwindling their numbers. Then we would dig.
We started our eagle-eyed capture of foragers. One, two, three, ten. Slowly ants stopped leaving the nest. We waited a few minutes without seeing any ants out and about. I took a long stick and plunged it into the nest. A few angry workers boiled out and we grabbed them. I probed again, mining for the black gold. A few more ants took the bait, but then nothing. No matter how much I cajoled, no more would venture out. They knew there was danger outside, and were crouched in darkness, waiting. It was time to dig.
‘Are you ready Walter?’ My eager helper was white as a sheet, anxious like me to get this over with. We both took a deep breath, and on the count of three, plunged our shovels into the rich black earth.
Instantly, the furious workers started boiling out. As I dug further, Walter stalked the workers with his forceps, grabbing ants before they could reach our boots and attack. He tossed dozens of ants into our buckets, black ants flying through the air one after the other. The provoked ants were making a huge racket, squeaking as loud as any forest frog or horny cricket. They were actually speaking to each other! The alarm signal, a high pitched squeaking sound, came from rubbing two parts of their hardened exoskeleton together. ‘Attack, attack!’ seemed to be the message. Quickly our buckets began to fill, and the squeaking was audible over monkey calls and parrot guffaws. The war cry of the bullet ant filled our ears.
Ever deeper we dug, and yet the queen kept retreating further under the tree, deep into the curving roots. A flash of white amidst the waves of black workers- we had just opened a brood chamber, where the immature ants were raised and protected. The nurses carrying worm-like white larvae and cocoon enshrouded pupae were quickly tossed into their own bucket. We had the foragers, the guards, the nurses captured for chemical analysis. The queen must be close!
‘Walter’, I said, eyes never leaving the wave of ants, ‘I’m going to pull the sapling down.’ It was the only way to get to the queen, and the reason I had chosen this nest, for its accessibility. The tide of ants had ceased, with the queen and her last entourage retreated into the deepest of their tunnels. I grabbed the tree, careful that no ants were along its length, and pulled down, hard. Suddenly, Walter screamed, and convinced he had been stung, I turned to see a huge bullet ant crawling up his mosquitoe netting right in front of his face. Staring cross-eyed at the squeaking horror, Walter froze as I swatted the stray ant off. That was close.
Alas, the Pentaclethra roots reached too deep. We could not reach into the deepest tunnels with our small shovels. We gathered our buckets of ants, about two hundred in total, and hiked back to camp. Deep in the jungle we left the queen in her ruined nest, her chemical brand still a mystery. And there too we also left the mystery of the sting. For we had escaped unscathed, for today.
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| Paraponera clavata- the bullet ant. |
